Two-qubit logical operations in three quantum dots system

Łuczak, Jakub; Bułka, Bogdan R.

doi:10.1088/1361-648x/aabe50

Cited by 4 publications

(3 citation statements)

References 69 publications

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“…V). While non-local gating has been studied in the literature [46,47], the exact gate sequence (including local gates) for capacitively coupled EO qubits has not been reported, to our knowledge. We show the exact sequence and timings in Fig.…”

Section: Non-local Gate Timementioning

confidence: 99%

Two-qubit sweet spots for capacitively coupled exchange-only spin qubits

Feng,

Zaw,

Koh

2021

Preprint

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The implementation of high fidelity two-qubit gates is a bottleneck in the progress towards universal quantum computation in semiconductor quantum dot qubits. We study capacitive coupling between two triple quantum dot spin qubits encoded in the S = 1/2, Sz = −1/2 decoherence-free subspace -the exchange-only (EO) spin qubits. We report exact gate sequences for CPHASE and CNOT gates, and demonstrate theoretically, the existence of multiple two-qubit sweet spots (2QSS) in the parameter space of capacitively coupled EO qubits. Gate operations have the advantage of being all-electrical, but charge noise that couple to electrical parameters of the qubits cause decoherence. Assuming noise with a 1/f spectrum, two-qubit gate fidelities and times are calculated, which provide useful information on the noise threshold necessary for fault-tolerance. We study two-qubit gates at single and multiple parameter 2QSS. In particular, for two existing EO implementations -the resonant exchange (RX) and the always-on exchange-only (AEON) qubits -we compare two-qubit gate fidelities and times at positions in parameter space where the 2QSS are simultaneously single-qubit sweet spots for the RX and AEON. These results provide a potential route to the realization of high fidelity quantum computation.

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Section: Non-local Gate Timementioning

confidence: 99%

Two-qubit sweet spots for capacitively coupled exchange-only spin qubits

Feng,

Zaw,

Koh

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Next, the generalised Hadamard gate (

G H

) operation [26, 43, 49] is performed by Alice on the particle

t

. The gate

G H

has the form of

G H = \frac{1}{\sqrt{d}} \sum_{k, k^{'} = 0}^{d - 1} e^{\frac{2 π i}{d} k k^{'}} | k 〉 〈 k^{'} | .

…”

Section: Point‐to‐point Non‐destructive Teleportation With a D‐dimens...mentioning

confidence: 99%

“…In addition, it should be noted that the quantum logic gates are the building blocks of quantum circuits in quantum teleportation. Multi‐qudit operation [43–46] requires a combination of single‐qudit gates and two‐qudit entangling gates, such as controlled‐NOT (

C N O T

) gate or controlled‐Z (

C Z

) gate [43]. In the past decades, several groups have demonstrated high fidelity single‐qudit gates [47] and two‐qudit gates in some systems [51], such as photons [16], ions [46, 48], superconducting qudits [49], and quantum dots [50].…”

Section: Introductionmentioning

confidence: 99%

Multi‐hop non‐destructive qudit teleportation via non‐maximally entangled GHZ channels

Liu

Wei

Xue

et al. 2021

IET Quantum Communication

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A scheme for the multihop non-destructive teleportation of an arbitrary single-qudit state based on various non-maximally entangled Greenberger-Horne-Zeilinger channels is proposed here. The parallel entanglement swap is used to form a direct ddimensional (d ≥ 2) entangled channel shared between the sender and the receiver. The authors' propose a novel idea that the third-party Charlie with high quantum information processing technology executes the channel modulation, which reduces the technical requirements of the sender and the receiver. In addition, if the teleportation fails, the unknown state will be restored by the sender. This work provides a feasible method for teleportation and ensures the integrity of the unknown quantum information.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

show abstract

Two-qubit sweet spots for capacitively coupled exchange-only spin qubits

2021

View full text Add to dashboard Cite

The implementation of high fidelity two-qubit gates is a bottleneck in the progress toward universal quantum computation in semiconductor quantum dot qubits. We study capacitive coupling between two triple quantum dot spin qubits encoded in the S = 1/2, Sz = −1/2 decoherence-free subspace—the exchange-only (EO) spin qubits. We report exact gate sequences for CPHASE and CNOT gates, and demonstrate theoretically, the existence of multiple two-qubit sweet spots (2QSS) in the parameter space of capacitively coupled EO qubits. Gate operations have the advantage of being all-electrical, but charge noise that couple to electrical parameters of the qubits cause decoherence. Assuming noise with a 1/f spectrum, two-qubit gate fidelities and times are calculated, which provide useful information on the noise threshold necessary for fault-tolerance. We study two-qubit gates at single and multiple parameter 2QSS. In particular, for two existing EO implementations—the resonant exchange (RX) and the always-on exchange-only (AEON) qubits—we compare two-qubit gate fidelities and times at positions in parameter space where the 2QSS are simultaneously single-qubit sweet spots (1QSS) for the RX and AEON. These results provide a potential route to the realization of high fidelity quantum computation.

show abstract

Two-qubit logical operations in three quantum dots system

Cited by 4 publications

References 69 publications

Two-qubit sweet spots for capacitively coupled exchange-only spin qubits

Two-qubit sweet spots for capacitively coupled exchange-only spin qubits

Multi‐hop non‐destructive qudit teleportation via non‐maximally entangled GHZ channels

Two-qubit sweet spots for capacitively coupled exchange-only spin qubits

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